NATURE 



{Jtme 30, 1881 



so that last night it crossed the path of Brorsen' s comet 

 of April 30, 1879. R. S. Newall 



Ferndene, June 28 



Photograpliic Spectrum of Comet 



On Friday night (June 24) I obtained, with one hour's 

 exposure, a photograph on a gelatine plate of the more 

 refrangible part of the spectrum of the comet which is 

 now visible. This photograph shows a pair of bright 

 lines a little way beyond H in the ultra-violet region, 

 which appear to belong to the spectrum of carbon (in 

 some form) which I observed in the visible region of the 

 spectra of telescopic comets in 1866 and 1868. There is 

 also in the photograph a continuous spectrum in which 

 the Fraunhofer lines can be seen. These show that this 

 part of the comet's light was reflected solar light. 



This photographic evidence supports the results I 

 obtained in 1868, showing that comets shine partly by 

 reflected solar hght, and partly by their own light, the 

 spectrum of which indicates the presence in the comet of 

 carbon, possibly in combination with hydrogen. 



Upper Tulse Hill, June 27 William Huggins 



Comet 1881 (5 was well observed at the Royal Observa- 

 tory, Greenwich, on June 24 and 25. Its position was 

 determined on both evenings with the altazimuth and 

 transit-circle. The following are the places deduced 

 from the meridian observations (uncorrected for parallax 

 and aberration) : — 



G.M.T. R.A. N.P.D. 



h. m. s. h. m. s. . , „ 



1881 June 24 ... II 25 40 ... 5 38 38-94 ... 40 35 39 

 25 - II 25 55 ■■• 5 42 5i'o6 ... 36 39 30 



The observation on June 25 indicates the following 

 corrections to the ephemeris computed by Mr. Lohse 

 from the elements communicated by the Emperor of 

 Brazil (Dunecht Circular, No. 21) : — Correction in R.A. 

 ■\- 9m., in Dec. + 6° 23'. On June 24 the head was 

 estimated to be brighter than Vega or .'Vrcturus, not- 

 withstanding its low altitude, and on June 25 it 

 appeared decidedly brighter than Arcturus, the star 

 being at about 10° greater altitude than the comet. 

 The tail, which was slightly curved (convex towards 

 the preceding side), was traced to a distance of about 

 8° on June 24, and 10° or more on June 25, its general 

 direction pointing to the star 2 Ursas Minoris, about 

 3° east of Polaris. With the Sheepshanks equatorial 

 (6| inches aperture) the head showed the want of 

 symmetry that has been remarked in some other 

 comets. On June 24 the preceding side was much the 

 brighter, there being a strong brush or arc of light on that 

 side, with a bright fan close to the nucleus and a much 

 smaller arc on the following side, the two arcs appearing 

 to spring from the nucleus on opposite sides, and higher 

 up to interlace. Avery remarkable feature was a straight 

 wisp of light extending from the nucleus nearly along the 

 a.xis of the tail. On June 25 this had become much loss 

 striking, and the appearance of the head had entirely 

 changed. The following side was then much the brighter, 

 and the general appearance was that of a parabolic enve- 

 lope, with a much brighter unsymmetrical parabola placed 

 within it, the latter having its focus on the following side 

 of the nucleus, and its axis turned round in the direction 

 np sf from that of the tail. 



The greater part of the head gave a bright continuous 

 spectrum, obliterating the u^ual cometary bands, but one 

 portion showed three bands, in the green, blue, and violet 

 respectively. Measures of the principal band in the green 

 showed that it coincides with the band in the first 

 spectrum of carbon (blue base of flame) at 5165, and not 

 with that of the second spectrum (vacuum-tube) at 5198. 



The bands in the blue and violet appeared to correspond, 

 as nearly as could be estimated, with bands in the first 

 spectrum of carbon. These observations were made 

 with the half-prism spectroscope mounted on the I2j-inch 

 equatorial, a dispersive power of about i8^° from A to H 

 being used, with a magnifying power of 14 on the view- 

 telescope, as in the measures of star-motions in the line 

 of sight. No decided polarisation gwas detected either 

 in the head or the tail. Cloudy weather has prevented 

 any observation of the comet since June 25. 



W. H. M. Christie 

 Royal Observatory, Greenwich, June 28 



In a letter to the Times of the 25th inst., Mr. Ranyard 

 says of Comet l> 1881, at present visible in the northern 

 heavens : — " In general brightness it decidedly outshone 

 the star Capella. . . . With a direct-vision spectroscope 

 of five prisms, and a 3J-inch telescope, its nucleus and 

 head gave a continuous spectrum, on which I could not 

 detect any bright bands." Last night, June 27, shortly 

 before midnight, the brilliancy of the nucleus had con- 

 siderably decreased, and yet with a five-prism direct-vision 

 spectroscope I could see most clearly, along with the 

 continuous spectrum, three green bands, not only in the 

 nucleus, but also in the surrounding coma. Two of the 

 bright lines were still strong in the neighbourhood of 

 the nucleus, even where the continuous spectrum was 

 very faint. I used an ordinary Browning spectroscope 

 on an 8-inch achromatic. A small McClean's spectro- 

 scope gave only the continuous spectrum, as seen by Mr. 

 Ranyard. This was, I think, due merely to the brightness 

 of the continuous spectrum ; for in the Browning instru- 

 ment the bright lines over the continuous spectrum were 

 not very conspicuous with a wide slit, but on narrowing 

 the slit the green bands became much brighter than the 

 rest of the spectrum. 



On June 25 the night was rather cloudy, but good ob- 

 servations for position were obtained by observing the 

 transit of the comet and of 6 Auriga: over the wires of an 

 eyepiece of the equatorial. The mean of four Avires gave 

 R.A. 5h. 42m. 51-345., at G.M.T. i2h. iim., the North 

 Declination being 53° 30' 57"-6. 



On June 27, towards midnight, the double envelope 

 surrounding the nucleus was clearly defined in the tele- 

 scope, as was also the bright bundle of rays, which spread 

 out in the direction of the sun and extended to a point in 

 the coma about half way between the bounding lines of 

 the inner and the outer envelopes. The direction of 

 these bright rays, which were very vivid, was not quite 

 opposite the direction of the tail, and the latter was very 

 slightly curved. 



A transit of the comet, sub Polo, was observed last 

 night, June 27, at G.M.T. iih. 3Sm., and this, combined 

 with the corrected reading of the meridian circle, gives 

 the following position : — R.A. 5h. 52m. 46-31S., North 

 Declination 60° 13' 40" -6. The length of the tail, clearly 

 discernible to the naked eye, was last night about 9'. 



S. J. Perry 



Stonyhurst Observatory, Whalley, June 28 



The following places have been obtained with the 

 transit-circle when the comet passed sub Polo : — 



Greenwich Mean Observed Observed North Polar 



Dale. Time of Right distance (uncorrected 



observation. Ascension. for paralla.\). 



h. m. s. h m. s. . , „ 



(fl) June 23 ... II 31 54-2 ... 5 35 55-2 ... 44 53 20-6 

 (/') „ 24 ... II 30 42-6 ... 5 38 39-9 ... 40 35 337 

 {c) „ 25 ... II 30 58-3 ... 5 42 52-2 ... 36 38 27-4 

 W) „ 27 ... II 33 2-8 ... 5 52 50-2 ... 29 46 S'S 

 Remarks. — (a) The nucleus distinct but nebulous. Tail 

 bright, and estimated 15° in length. Observation good. 



(b) Observation difficult, owing to cloud. 



(c) Nucleus better defined than on June 23, but not so 

 bright. Length of tail estimated at 15°. Observation good. 



(a') Observation fair, very cloudy. Tail I2°-1 5° in length 

 Radcliffe Observatory, Oxford E. J. STONE 



